[eagle] Re: Another idea on phased array configuration

Bill Ress bill at hsmicrowave.com
Fri Apr 27 13:01:36 PDT 2007


Thanks for your reply.

I'll get with John Stephensen and kick some "West Coast" ideas around. 
Didn't you have some amplifier guru's on the East Coast? Perhaps they 
can weigh in.

Since this widget will surely drive the satellite power consumption 
issue, perhaps it should be high up on this year's "action item" list.

Regarding satellite power generation, I used the Eaglepedia info 
indicating 6 solar panels and the stated goal of 100 watts (perhaps it 
is out of date??). Then I remembered your talk at the 2006 symposium 
which showed a 12 panel fold out design. So have we better refined what 
power the satellite will provide??

Robert McGwier wrote:
> Bill Ress wrote:
>> Bob,
>> I don't think we'll find a device on the current marketplace that 
>> will suit our efficiency needs. But, if we're willing to develop 
>> (fund) a program to design and build a Class E, 1 watt, 5.7 GHz  
>> amplifier module, we might get to 70 and maybe 90% efficiency. I have 
>> seen Class E X Band amplifiers with 60 to 70%. The design, including 
>> the choice of active device(s) must start with the goal of being 
>> Class E since several interesting parameters are in play. You just 
>> can't take a Class C amplifier and "push" it into the switching mode. 
>> Perhaps a Class C amplifier might be enough.
> I am listening and more than willing to consider anything that gets 
> the job done with a reasonable budget.
>> But it's a very interesting design challenge - to be sure!! When do 
>> we start??
>> But, lets assume that we build amplifiers with 100% efficiency. 36 or 
>> 43 elements still requires 36 to 43 watts input. What has me 
>> concerned is that the current satellite structure design calls for 6 
>> solar panels with, what I guess is about 25 watts per panel. That 
>> appears to be consistent with the 100 watts power generation stated 
>> in the current Eagle Functional Requirements.
>> Are we still working with 100 watts or did I miss something??
> What we are working with is "whatever we can get away with" so long as 
> it meets the communications systems goals as stated in our working 
> document from the San Diego meeting of last summer.  That is the 
> system we want to design and the concept we wish to support.  If this 
> involves us working on our own amplifier design, and not using 
> monolithic designs from Hittite, etc.,  so be it.  The efficiency 
> translates directly to multiple scenario big wins for us.  Class E for 
> this is completely acceptable.
>> Regards...Bill - N6GHz
>> Robert McGwier wrote:
>>> The Hittites were interesting,  they had potential, but they are not 
>>> really efficient enough.  We will find better parts.
>>> Bob
> 73's
> Bob
> N4HY

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